ci: add GitHub Actions workflow

- Add .github/workflows/ci.yml with pytest, coverage, linting, and type checking
- Test on Python 3.11 and 3.12
- Exclude slow tests by default
- Upload coverage reports as artifacts
- Add CI/CD documentation to AGENTS.md

AGENTS.md

@@ -350,4 +350,44 @@ video_url|anime_page_url|episode_title
 - `pytest-cov` - Coverage reporting
 - `pytest-mock` - Mocking utilities
 - `pytest-timeout` - Test timeout protection
-- `pytest-html` - HTML test reports
+- `pytest-html` - HTML test reports
+
+
+## CI/CD
+
+### GitHub Actions
+
+This project uses GitHub Actions for continuous integration. The workflow is defined in `.github/workflows/ci.yml`.
+
+**Workflow Features:**
+- Runs on push and pull requests to `main` and `dev` branches
+- Tests on Python 3.11 and 3.12
+- Excludes slow tests by default (`-m "not slow"`)
+- Generates HTML coverage reports
+- Runs linting with ruff
+- Runs type checking with mypy
+
+**Artifacts:**
+- Coverage reports are uploaded as artifacts after each run
+- Access via the "Actions" tab on GitHub
+
+**Running locally:**
+```bash
+# Run tests (excluding slow tests)
+pytest -m "not slow" --cov=app --cov-report=html
+
+# Run all tests including slow ones
+pytest
+
+# Run only unit tests
+pytest -m "unit"
+
+# Run only integration tests
+pytest -m "integration"
+
+# Run linting
+pip install ruff && ruff check app/
+
+# Run type checking
+pip install mypy && mypy app/
+```